This invention relates to a means for capturing toxic waste gases formed as byproducts during metalurgical processes in converters. More particularly, the device to be described hereinafter is adapted to be used with a converter of drum shaped configuration, and suitably supported on rollers and gear driven to move in an arcuate manner between one of four positions describing an arc. The motor range is from 0.degree. to 180.degree., defined by motion of the mouth of the converter with 0.degree. being the topmost point of the converter. As a practical matter, the range of motion is preferred to be between 0.degree. and 135.degree. to receive or to discharge material.
One of the most vexing problems from not only an environmental point of view, but also to minimize workplace contamination from deadly toxic waste fumes during certain conversion processes is capturing waste gases from extremely hot furnaces. Vessels used in metalurgy operate at exceeding high temperatures within a refractory environment up to 1300.degree. Centigrade and the expulsion of toxic gases from the molten constituents is not uncommon.
Common operations associated with metalurgical conversion processes includes allowing the converter to discharge all or a portion of its contents from a previous conversion run, orientation of the converter vessel to receive one or more components for subsequent conversion and a reaction step in which tuyeres or their equivalent are caused to blow enough volume of air which react with the constituents in the converter and elevate the temperature.
The following citations reflect the state of the art of which applicant is aware in so far as these patents appear to be germane to the patent process at hand:
U.S. Pat. No. 3,365,340--Tisdale PA1 U.S. Pat. No. 3,727,587--Nebgen PA1 U.S. Pat. No. 4,106,758--Leroy et al. PA1 U.S. Pat. No. 4,129,283--Laimer et al. PA1 U.S. Pat. No. 4,190,237--Baum
The patent to Baum is of interest since he teaches the use of a method for treating waste gases emitted from a converter wherein both a waste gas cooler and dust separator are utilized. Particularly, Baum is concerned with the discharge of carbon monoxide into the atmostphere and proposes as a solution therefor an arrangement for minimizing the amount of atmospheric air that can be mixed with the exhaust gases by containing the exhaust gases in a fairly constricted environment as shown in the drawing figures. More particularly, the contents of the refining vessel is kept substantially excluded from the environment until the pouring or the addition of further materials, and a rather cumbersome shroud 1 or pressure vessel is required to effect a substantially gas tight connection, the device obviously being somewhat cumbersome and requiring substantial manipulation to utilize same since Baum reduces the amount of atmospheric air associated with the waste gas. This citation requires that the refining be done under pressure and therefor has an associated gas tight seal as a result.
The patent to Leroy et al discloses a converter for refinement of liquid metal wherein two gas scavenging devices 14, 17 are provided for the subsequent disposition of the waste gases. This citation uses a converter for refining liquid metal of substantially cylindrical configuration having closed end walls and an opening in the circumference thereof, the body being arranged with an horizontal axis and being rotatable thereabout.
Regarding the exhaust scavenging, in one position "or the normal position" an opening lies in substantial registry with the first device 14 for collection of gases, and the second gas collection device 17 is oriented to receive the vapor from the converter when in a second position as shown in FIG. 2.
Nebgen relates to a copper converter wherein gaseous products produced during the burning of copper sulfide to sulphur dioxide are conducted through a tight air hood wherein both heat and recoverable constituents in the waste gases are obtained. A cursory review of this citation makes it evident that the gases can only be scavenged from one position of the converter relative to the exhaust flue.
Laimer et al. shows a metalurgical vessel having a hood for diverting flue gases and smoke to a remote area to avoid contamination. As should be evident, the outlet spout is provided with a covering and an associated shroud to assist in gas migration through conduits 25 for example, the opening 21 and the need to have access to a portion exterior the shroud allows the amount of waste gases entering the environment to perhaps be reduced, but only at the cumbersome expense of providing a recess within which the pouring and ladling off can occur in a sealed or closed manner as suggested in column 1 lines 44-52.
Moreover, the actual observation of ladling from the vessel to another container, since it occurs in a closed environment requires a viewing port or remote television camera to monitor same, and the smoking gases associated with the transfer would appear to hamper the visual process.
Tisdale shows the state of the art further, and more particularly a basic oxygen furnace wherein fumes containing iron oxide are directed into a hood 2 and through a duct 3 to impinge on slag contained within an acid air furnace 6. Note that after the fumes impinge on the slag they flow into a waste heat chamber 15 and into a spray chamber 19 wherein the fumes are cooled and cleaned of dust.
By way of contrast, the instant application is distinguished over the known prior art in that an instrumentality has been provided which lends itself to disposition on cylindrical or drum shaped converters which are adapted to move in arcuate fashion from a first to a plurality of further positions. An opening associated with the migration of metals, slag, etc. associated with processes earmarked for the converter address the converter mouth during various angles of orientation of the converter offset from a vertical plane, in which the centerline of the opening is coincident with a vertical plane. An instrumentality is provided which is carried upon the converter proper and can travel with the converter in its several various postures and provide a sufficient air flow and circulation to facilitate the migration of noxious and toxic fumes out of the environment and the work place into a station remote therefrom for subsequent treating.
More particularly, a conduit means is adapted to communicate adjacent the opening of the converter at one edge and a source of air pressure is adapted to pass a volume of air from this one side edge of the converter mouth to another. The other side edge of the converter remote from inlet air pressure has a negative pressure area communicating with a further conduit which encourages the migration of exhaust gases from the mouth of the converter thereto and to subsequent treatment downstream. This defines a "push-pull" air flow system.
Since the converter moves from at least one position to a plurality of further positions, the conduits associated with the converter and defining the "push-pull" system similarly need the requisite flexability to move in an arc of circle corresponding to the degree of rotation of the converter so that the air flow and exhaust gas scavenging can occur during all aspects of the converter orientation. To this end, the inlet duct is provided with a flexible instrumentality to allow deformation of the flexible portion thereby allowing the inlet duct to assume a plurality of angulations. The exhaust duct has a swivel portion coincident with the axis of rotation of the converter and a portion of the exhaust duct instrumentality operates and rotates in concert with the converter. Various structural nuances associated with the apparatus according to the instant invention will become evident.